1. Field of the Invention
The present invention relates to a novel, advantageous, and economic process of producing N-sulfo alkane amino alkane phosphonic acids and their water-soluble salts, to novel compounds obtained by said process, to compositions containing same, and to methods of using such compositions.
2. Description of the Prior Art
U.S. patent application Ser. No. 891,043 of KLAUS SOMMER and HERMANN WEBER discloses novel and highly advantageous N-sulfo alkane amino alkane phosphonic acids and their water-soluble salts. According to said application, such compounds are prepared by reacting an alkali metal salt of an amino alkane phosphonic acid in an alkaline solution with an alkali metal salt of a halogen or hydroxy substituted alkane sulfonic acid in a molar proportion between about 1:1 and about 1:2 of phosphonic acid reactant to sulfonic acid reactant, while heating. To carry out this process it is usually necessary to heat the reaction mixture to boiling under pressure at a temperature between about 180.degree. C. and about 240.degree. C.